1. Field of Invention
The present invention relates to a bumper beam for a vehicle, a manufacturing method therefor and a bumper beam unit thereof. More particularly, the present invention relates to a bumper beam for a vehicle having fastening plates formed as one unit with two steel pipes and stays and injection molded with a resin group material as one unit in a hybrid mode; a manufacturing method therefor and a bumper beam unit thereof.
2. Description of Related Art
In general, the bumper in the vehicle is a damping device mounted to predetermined parts of a front and a rear of the vehicle for absorbing an impact of a crash when the vehicle crashes to another vehicle or a fixed body for devising safety of occupants as well as minimizing deformation of a vehicle body.
Referring to FIG. 1, the bumper 100 is provided with a bumper beam 101 disposed in a width direction of the vehicle at the front and the rear thereof, a stay 103 for connecting the bumper beam 101 to a side member 111 of the vehicle body, an energy absorber 107 disposed in front of the bumper beam 101 for absorbing the impact, and a bumper cover 109 for covering the bumper beam 101 and the energy absorber 107.
In this case, the bumper beam 101 is formed of a material, such as steel, aluminum, fiber reinforced plastic, for supporting the energy absorber and, at the same time with this, absorbing external impact energy as the bumper beam itself is deformed.
Recently, a system is introduced, in which a steel pipe is inserted in the bumper beam of steel for reinforcing crush stiffness of the bumper beam, additionally, which increases cost and vehicle weight resulting in conflict with fuel consumption saving of the vehicle.
Therefore, recently, as a scheme for making the vehicle lighter to improve the fuel consumption, a bumper beam is spot lighted, which is formed of a GMT (Glass Mat Reinforced Thermoplastics) material which is one of plastic materials.
The bumper beam of the GMT material has excellent physical properties enough to have an advantage in that damage to the vehicle can be minimized by absorbing the impact energy when the vehicle crashes.
The bumper beam of the GMT material is fabricated with steps of impregnating glass fiber on a polypropylene sheet, and impregnating a polypropylene sheet thereon again to form a resin sheet which is subjected to vacuum molding to obtain the bumper beam of GMT.
However, the bumper beam of GMT material has a drawback in that the beam is broken at a high speed crash exceeding a fatigue limit, and since the bumper beam of the GMT material is required to be thick on the whole for providing required rigidity and strength, the bumper beam of GMT material has a problem in that mounting space and weight reduction effects are not high substantially in comparison to a steel beam.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.